Detection of hazardous materials is important for national security and defense. There are typically two conventional approaches to the detection of hazardous materials: passive techniques and active interrogation techniques.
Conventional passive techniques can be used to detect nuclear material, for example, by direct measurement of the nuclear radiation, mainly gamma rays and neutrons. However, there are many disadvantages with respect to conventional passive detecting techniques. For example, conventional passive techniques are typically heavy, bulky, and expensive for a long distance remote detection. Moreover, conventional detectors using passive techniques cannot detect shielded nuclear material at remote distances. Also, because passive methods rely on the direct detection of gamma rays and neutrons, which cannot be done from a significant distance (>100 m), a user of a passive technique can be exposed to a high dose of radiation.
Conventional active interrogation techniques, which use neutron, gamma ray, or muon beams, for example, are also used to detect hazardous materials. However, many disadvantages arise from the use of such conventional active techniques. These disadvantages include poor reliability and the potential to detonate a hazardous material such as a nuclear bomb located in a target area.
Due to the disadvantages of conventional passive and active methods to detect hazardous material, it is obvious that systems and methods to safely and remotely detect such material would be of great interest. The present invention, which will be discussed further below, provides such systems and methods.